A panel component comprising steel plates with the same quality and with the same or different thicknesses is used as a blank for formation into, for example, a chassis panel of an automobile.
Conventionally, a panel component comprising, for example, steel plates with different thicknesses in combination has been produced such that plates with thick and thin thicknesses are firstly punched out, for example, by presses into required shapes and are individually formed and then are connected together, for example, through spot welding to thereby assemble the panel component. However, such process is disadvantageous in increased production cost due to much working man-hour. In order to overcome the problem, it has been also carried out that an entire panel component is made from a single thick steel plate, which may disadvantageously lead to increase in weight and in cost.
To overcome these and to produce a blank for formation of, for example, a chassis panel of an automobile, recently used is a process such that, for example, steel plates with different thicknesses are butted together and are integrated into a so-called tailored blank through CO2 (carbon dioxide) laser welding, plasma welding, etc. According to this process, for example, steel plates with thick and thin thicknesses are butt-welded into a tailored blank which may be, for example, press-formed into a panel component with a predetermined shape.
Thus, the above-mentioned process using a tailored blank has effects of substantially reducing working man-hour and production cost in comparison with assembling of a panel component by, for example, spot welding and is advantageous in weight reduction in comparison with formation of an entire panel component from a single thick steel plate. Moreover, in the process of forming a panel component from a tailored blank, discards or scraps from various pressing processes may be utilized, advantageously resulting in reduction of waste of and increase in yield of material. Furthermore, the tailored blank, which has been integrated through continuous welding of steel plates, has an advantage that it has welding strength substantially increased in comparison with use of spot welding.
In order to produce a tailored blank through, as mentioned in the above, butt-welding of for example steel plates with thick and thin thicknesses, the steel plates are positioned into mutual abutment at their opposing ends for formation of weld line in place. A reference positioning mechanism used therefor is disclosed in below-mentioned Reference 1.
Such reference positioning mechanism is worked with first and second tables divided on which one and the other plate members to be butt-welded are rested, respectively, said tables being relatively movable toward and away from each other. Firstly, with the tables being separated, the one plate member on the first table is caused to abut at its end against a reference plate upwardly protruded over an upper surface of the first table, and is locked with the end being positioned. Then, the reference plate is retracted below the upper surface of the first table; and the second table is moved toward the first table to make the other plate member on the second table abut at its end against the positioned one plate member on the first table, thereby providing weld line between the plate members.
[Reference 1] JP 2001-287090A